Reproduction and postnatal growth of the Cabrera vole, Microtus cabrerae, in captivity

Abstract

Three pairs of the endangered Cabrera vole, Microtus cabrerae, which is endemic to the Iberian Peninsula, were captured in the wild and reared in captivity. They did not breed under standard laboratory conditions, and bred only under conditions similar to those found in wild colonies. Six litters were obtained and a total of 24 pups were monitored. Five external variables were measured and timing of 11 developmental events was recorded for each pup until it was 80 days old. Litter size was 4.0 ± 0.89 (mean ± SE; range = 3–5) pups per female, falling within the range reported for other Microtus species. Litter size of M. cabrerae was lower in the laboratory than in the field. Female body mass was correlated with litter mass at birth. Newborns were heavy (3.5 g, on average) compared with those of other Microtus species because of the relatively large size of adult M. cabrerae. Timing of the main developmental events followed a similar pattern to that observed for other species of the genus. Juvenile M. cabrerae grew fast in length during lactation, rapidly increasing their body mass during postweaning. Observations on parental behaviour in rearing pups support the previously published hypothesis that the species is monogamous. A global assessment of our results suggests that M. cabrerae should be included among the species that use the K strategy of reproduction.